Plans to introduce police vans equipped with five cameras filming inside and outside the vehicle have raised concerns about privacy.

The cameras are apparently meant to "improve road safety" but will further add to the thousands of surveillance devices around the city. Then there are the body cameras planned for the Police Tactical Unit and a scheme by the Fire Services Department to mount cameras on fire engines and ambulances.

Lawmaker James To Kun-sun, vice-chairman of the Legislative Council security panel, called the latest plan an intrusion of privacy.

"Now it is as though all the disciplined services are installing CCTV everywhere on the street ... Soon Hong Kong will be like the society described in 1984," he said, referring to the novel by George Orwell which features omnipresent government surveillance.

Police Inspectors' Association chairman Benjamin Tsang Chiu-fo said officers agreed with the plan once they were assured interior cameras would only film the dashboard, not the occupants.

One police source said 20 to 30 new police vans fitted with the cameras would be introduced first - with the cameras' audio recording functions switched off.

A police spokesman said the system would be introduced early next year and would consist of five non-rotatable cameras, with two mounted in front, one at the lower back, one at the lower left front and one covering the dashboard.

He added that the measure was aimed at improving safety awareness among police drivers and other road users and providing evidence in accidents involving police cars.

But Andrew Shum Wai-nam, a member of Civil Human Rights Front, said it would be like "mobile eyes" watching residents. "I can't see there are many accidents related to police cars," he said.

The spokesman said the police force had received legal advice that the system complied with privacy laws.

The cameras would start only when the engine was turned on, and images would be overwritten every four hours.

Another source said ultimately all police vehicles, including motorcycles, could be equipped with cameras. But the spokesman did not confirm or deny this. He also did not provide accident figures relating to police cars.

This article appeared in the South China Morning Post print edition as: